A microscope is generally used for observation of a sample at each depth by adjusting focal point alignment. Especially, a confocal microscope has an excellent resolution in a direction of the optical axis and enables observation of an optical slice image of a sample having a three dimensional structure. Thus the microscopes, in recent years, have been rapidly employed widely in the fields of medicine and biology as optical observation means. FIG. 5 illustrates a fundamental configuration of the confocal microscope. Referring to FIG. 5, a laser light beam emitted from a laser light source 1 is converged, for example, using microlenses of a lens array disc 9 in a double rotating disc 2 (described later), transmitted through a dichroic mirror 11, focused in a pinhole of a Nipkow disc 10, which is another rotating disc, and emitted from the pinhole; the sample is irradiated with the laser light beam from the pinhole through an objective lens 14, fluorescence emitted from the sample by excitation is propagated on the same path in the opposite direction as the observation light beam and is caused to pass through the same pinhole (a so-called confocal point) to thereby conduct measurement.
The measurement is conducted in a manner such that fluorescence after passing through the pinhole is reflected on the dichroic mirror 11 and then converged by a convex lens 12 and directed to a high speed CCD camera 3. In a case where a live tissue is observed with such a confocal microscope (for example, an observation of a mouse heart tissue), observation is performed with some level of effectiveness on the removed heart 20 or the like perfused using a cannula 21 and an observation site thereof is irradiated with a laser light beam while being monitored by an electrocardiogram measuring instrument 22.
Since a confocal microscope has high resolution in the optical axis, however, it is necessary to observe a live cell and a live tissue at different depth of observation in order to obtain three-dimensional images of the live cell and the live tissue in real time, which requires moving things each having a weight, such as the sample stage and the objective lens; therefore, a three dimensional observation in real time has been disabled (see, for example, a patent document No. 1 (JP-A No. 06-341955) and a non-patent literature No. 1 (OLYMPUS OPTICAL CO., LTD's catalogue “scanning laser microscope” retrieved Sep. 30, 2002 from a homepage of Internet,
URL: http://www.nagano-it.go.jp/seimitu/setubi/se-shuuseki10/se-04laser.html (column on specifications).